File Name: rock blasting and explosives engineering .zip
Fragmentation energy ratio is an important index to evaluate whether an explosive is used efficiently. This paper discusses the effect of water-decked blasting on fragmentation energy based on theory and numerical simulation, and three blasting tests were performed to measure the actual fragmentation energy at a granite-based field. Results show that at the same charge amount, the maximum borehole pressure of water-decked blasting is much greater than that of normal blasting in theory, which facilitates rock breaking.
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Please enter your email address. You will receive a link and will create a new password via email. Sorry, you do not have permission to ask a question, You must login to ask question. Become VIP Member. Do you need to remove the ads? The main objectives of controlled blasting techniques are to minimize the overbreak and fracturing of rock beyond the designated boundary of excavation to achieve smooth post-blast surface and to control wild flyrock and ground vibration within permissible limits.
This objective is normally achieved by minimizing and making judicious use of explosives in the blast holes. Techniques such as line drilling, pre-splitting, smooth blasting, and cushion blasting are carried out to achieve controlled blasting. The suitable parameters for controlled blasting are established through trial blasts. Usually, it needs to establish the optimum hole spacing and the charge per hole.
When an explosive charge is detonated inside a blast hole, it is instantly converted into hot gases, and the expanding gases exert intense pressure on the blast hole walls. A high-intensity shock wave travels through the rock mass, which attenuates sharply with distance. A major portion of the explosive energy passes beyond the fractured zone in the form of elastic ground vibrations. As seismic waves travel through the rock mass, they generate particle motions, which are termed as ground vibrations.
Even though the use of explosives has unwanted side effects in the form of vibration, explosives provide an inexpensive source of energy for rock excavation in mining and civil engineering projects.
Thus it is crucial to control the adverse effects of blasting. When a controlled blast is fired, the vibration level is controlled by two principal factors, distance and charge size.
Obviously, it is safer to be far away from a blast than to be near it. Various codes and standards have been prescribed for ground vibration limits in different countries. The recent trend is to refer to the frequency of the ground motion.
Low-frequency waves cause more damage to structures, particularly in the case of multi-storied buildings. For low-frequency ground vibration, the safe level of vibration from this curve is The most common method of controlling ground vibration is by minimizing the charge weight per delay. Delay blasting permits to divide total charge into smaller charges, which are detonated in a predetermined sequence at specified intervals.
Blasting without delay or sufficient delay numbers increases ground vibrations due to an increase in maximum charge per delay. The vibration can be significantly reduced by optimizing blast design parameters. It is suggested to establish optimum burden, hole spacing, powder factor, and hookup to control vibration. The main objectives of controlled blasting techniques are to minimize the over break and fracturing of rock beyond the designed boundary of excavation to achieve smooth post-blast surface and to control of fly rock and ground vibration within permissible limits.
The types in which controlled blasting is carried out are- 1. Line drilling 2. Pre-splitting 3. Smooth blasting 4. Cushion blasting. Line drilling is best suited to homogenous formations where bedding planes, joints, and seams are at a minimum. Smooth blasting is widely used for controlling overbreak in canals, underground headings, and slopes. Sign Up Sign Up to The Constructor to ask questions, answer questions, write articles, and connect with other people.
Have an account? Sign In Now. Free Signup or Login to continue Reading Remember Me! Don't have account, Sign Up Here. Forgot Password Lost your password? VIP Dashboard. How to Carry out Controlled Blasting of Rocks? Fig 1: Controlled Blasting of Rocks. Contents: Types of Controlled Blasting 1. Line Drilling 2.
Pre-Splitting 3. Smooth Blasting 4. Cushion Blasting Ground Vibration 1. Factors Affecting Vibration 2. Safe Limits of Vibration 3. What is the objective of controlled blasting? What are the type of controlled blasting? When is line blasting used? Which method of blasting is preferred for break-in canal, underground headings, and slopes? Previous article. Next article. Related Posts.
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madvirgin.org Explosives Engineering. ○ geometry of rock blasting. A free body diagram illustrating the explosive.
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The Geomining Technological Institute of Spain ITCE , aware of this progress and of the importance which the breakage process has acquired in mining and civil engineering projects, has ordered the publication of Drilling and Blasting of Rocks. Rock mass reinforcement by fully grouted rock bolts in a pattern adjacent to the planned piercing hole. Blasting Plan developed by a licensed blasting company. B Use wood, or other non-sparking material, for a. Rock mass properties influence the blast design and knowledge of these properties is very important for blast design . Implement best practice measures for the management and minimisation of dust and noxious fumes from surface blasting. During construction of the Airport Link tunnel portal.
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Rock Blasting and Explosives Engineering covers the practical engineering aspects of many different kinds of rock blasting. It includes a thorough analysis of t.Alice W. 17.05.2021 at 16:16
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Drilling and blasting is the controlled use of explosives and other methods such as gas pressure blasting pyrotechnics, to break rock for excavation.